1. Field of the Invention
This invention relates to an automatic cyto-screening device, more particularly to a diagnosis logic circuit or a classification logic circuit for an automatic cyto-screening device.
2. Description of the Prior Art
With the recent increase in the number of people who fall into the group examined for early diagnosis of cancer, the lack of experts for inspection of cells who are called cyto-screeners has become a problem. Accordingly, automatic cyto-screening devices are now being used for saving labor and improving the efficiency in the diagnosis.
The outline of a conventional automatic cyto-screening device will now be illustrated by reference to FIG. 1.
A selected portion of a stained sample 1 (formed by fixing, staining and enveloping a collected cell specimen on a preparation glass, in which several thousands to scores of thousands of cells are contained) is enlarged by an image-magnifier 2 such as an optical microscope, and the enlarged image is converted to an electric signal by a scanner 3, such as a television camera. By using this electric signal, it is determined by a cell detector 4 whether cells are present in the enlarged image (for instance, the determination is performed by calculating the area having a density higher than 50% of the maximum density). Where no cells are present in the enlarged area, the sample 1 is vibrated slightly automatically by a stage driver 5, and the same operation is conducted again. Where cells are detected, the electric signal of the enlarged image is fed to a diagnosis logic circuit 6 where, by calculating the parameter showing the morphologic feature of cells from the electric signal, it is determined whether respective cells are normal or abnormal and the results of the determination are memorized. Then, the sample is vibrated slightly and detection and diagnosis of subsequent cells continue. After the completion of diagnosis of all individual cells, based on the memorized data, it is determined whether this sample is normal or abnormal.
In conventional automatic cyto-screening devices having the above-mentioned structure, since high accuracy is required in diagnosis of this type, the greatest problem is the construction of the diagnosis is logic circuit, especially the manner in which it is determined whether respective detected cells are normal or abnormal.
In conventional automatic cyto-screening devices, the cytoplasmic area, the nuclear area and the nuclear mean density are used as parameters for determining whether respective cells are normal or abnormal, but sufficiently high accuracy in diagnosis cannot be attained in conventional devices. The following are two reasons for this defect.
Cells to be used for cyto-screening include many stratified squamous epithelical cells. Since these cells cause differentiation, the nuclear area and cytoplasmic area vary. For example, cells of the uterocervical portion to be used for early diagnosis of uterine cancer are stratified squamous epithelical cells. The above-mentioned parameters for the diagnosis logic circuit vary with differentiation of these stratified squamous epithelical cells.
Secondarily, the mean nuclear density is defective as a parameter in the following points:
1. The value is an amount indicating the general tendency in the nucleus, and minute changes in the nucleus cannot be determined by this value. PA1 2. The value varies depending on the stained level of the nucleus.
The classification rate is lowered by these defects.